linux-kernel - Re: [PATCH 11/11] perf kvm top: limit guest kernel info message to once

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Date:	Tue, 24 Jul 2012 08:02:52 -0600
From:	David Ahern <dsahern@...il.com>
To:	Arnaldo Carvalho de Melo <acme@...stprotocols.net>
CC:	linux-kernel@...r.kernel.org, Ingo Molnar <mingo@...nel.org>,
	Jiri Olsa <jolsa@...hat.com>,
	Namhyung Kim <namhyung@...nel.org>,
	Frederic Weisbecker <fweisbec@...il.com>,
	Peter Zijlstra <peterz@...radead.org>
Subject: Re: [PATCH 11/11] perf kvm top: limit guest kernel info message to
 once

On 7/23/12 12:17 PM, Arnaldo Carvalho de Melo wrote:
> Em Fri, Jul 20, 2012 at 05:25:56PM -0600, David Ahern escreveu:
>> 'perf kvm top' shows a continual flurry of:
>>      Can't find guest [5201]'s kernel information
>>
>> if it can't find the guest info and with a lot of VMs running a user
>> has no chance of reading them all. Limit message to once per guest.
>>
>> Signed-off-by: David Ahern <dsahern@...il.com>
>> Cc: Arnaldo Carvalho de Melo <acme@...stprotocols.net>
>> Cc: Ingo Molnar <mingo@...nel.org>
>> Cc: Jiri Olsa <jolsa@...hat.com>
>> Cc: Namhyung Kim <namhyung@...nel.org>
>> Cc: Frederic Weisbecker <fweisbec@...il.com>
>> Cc: Peter Zijlstra <peterz@...radead.org>
>> ---
>>   tools/perf/builtin-top.c |   14 ++++++++++++--
>>   1 file changed, 12 insertions(+), 2 deletions(-)
>>
>> diff --git a/tools/perf/builtin-top.c b/tools/perf/builtin-top.c
>> index 1706dc9..6285374 100644
>> --- a/tools/perf/builtin-top.c
>> +++ b/tools/perf/builtin-top.c
>> @@ -706,8 +706,18 @@ static void perf_event__process_sample(struct perf_tool *tool,
>>   	int err;
>>
>>   	if (!machine && perf_guest) {
>> -		pr_err("Can't find guest [%d]'s kernel information\n",
>> -			event->ip.pid);
>> +		static struct strlist *seen;
>> +		char pidstr[8];
>> +
>> +		if (!seen)
>> +			seen = strlist__new(true, NULL);
>> +
>> +		scnprintf(pidstr, sizeof(pidstr), "%d", event->ip.pid);
>> +		if (!strlist__has_entry(seen, pidstr)) {
>> +			pr_err("Can't find guest [%d]'s kernel information\n",
>> +				event->ip.pid);
>> +			strlist__add(seen, pidstr);
>> +		}
>
> Abuse of strlist? Can't we have an intlist?

Use of existing facility. :-) I'll look at adding an intlist facility.

David

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